Composite Films of Thermoplastic Starch and CaCl<sub>2</sub> Extracted from Eggshells for Extending Food Shelf-Life

Jeovan A. Araujo; Yvonne J. Cortese; Marija Mojicevic; Margaret Brennan Fournet; Yuanyuan Chen

doi:10.3390/polysaccharides2030041

Polysaccharides (Sep 2021)

Composite Films of Thermoplastic Starch and CaCl<sub>2</sub> Extracted from Eggshells for Extending Food Shelf-Life

Jeovan A. Araujo,
Yvonne J. Cortese,
Marija Mojicevic,
Margaret Brennan Fournet,
Yuanyuan Chen

Affiliations

Jeovan A. Araujo: Department of Polymer, Mechanical & Design, Materials Research Institute, Athlone Institute of Technology, N37HD68 Athlone, Co. Westmeath, Ireland
Yvonne J. Cortese: Department of Polymer, Mechanical & Design, Materials Research Institute, Athlone Institute of Technology, N37HD68 Athlone, Co. Westmeath, Ireland
Marija Mojicevic: Department of Polymer, Mechanical & Design, Materials Research Institute, Athlone Institute of Technology, N37HD68 Athlone, Co. Westmeath, Ireland
Margaret Brennan Fournet: Department of Polymer, Mechanical & Design, Materials Research Institute, Athlone Institute of Technology, N37HD68 Athlone, Co. Westmeath, Ireland
Yuanyuan Chen: Department of Polymer, Mechanical & Design, Materials Research Institute, Athlone Institute of Technology, N37HD68 Athlone, Co. Westmeath, Ireland

DOI: https://doi.org/10.3390/polysaccharides2030041
Journal volume & issue: Vol. 2, no. 3
pp. 677 – 690

Abstract

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Calcium chloride (CaCl2) has been widely used to maintain the quality of fresh-cut fruits and vegetables because it stabilizes and strengthens the membrane system against fungal attacks. It is mainly applied via spray coating and dip coating techniques. This study explored a method of incorporating calcium chloride extracted from eggshells in a packaging material, thermoplastic starch (TPS), via a hot-melt extrusion process. The composites were characterized by FTIR, DSC, SEM-EDX and tensile testing. FTIR confirmed the chemical reactions between CaCl2 and TPS. DSC results showed a significant decrease in the heat of fusion by adding 20 wt% of CaCl2 content in TPS, indicating a drop in the degree of crystallinity. The Young’s modulus of TPS was not significantly affected by the incorporation of 10 wt% CaCl2 (P = 0.968), but reduced notably with the addition of 20 wt% CaCl2 (P = 0.05), indicating the plasticizer effect of the CaCl2. Physiochemical analysis of fresh-cut apple slices was assessed. Samples placed on the surface of the TPS/CaCl2 composites displayed less pH reduction, reduced antioxidant activity, more weight loss and increased reducing sugar compared to the samples placed on the surface of virgin TPS films. CaCl2 released from the TPS/CaCl2 films was measured and their antimicrobial activity was confirmed by bacterial inhibitory growth assessment. Fungal growth was observed on apple slices placed on virgin TPS film by day 21 while apple slices placed on TPS/CaCl2 20 wt% composites did not support any fungal growth for 28 days. In summary, TPS and eggshell-extracted CaCl2 showed the ability to maintain the quality of fresh-cut apples, and TPS/CaCl2 10 wt% composite could be a good option as a packaging material for fresh-cut fruits due to active antimicrobial activity and maintained Young’s modulus.

Published in Polysaccharides

ISSN: 2673-4176 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science: Chemistry: Organic chemistry: Biochemistry
Website: https://www.mdpi.com/journal/polysaccharides

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